Bird Flu: What is Avian Influenza and is it present in the UK?

What is Bird Flu?

Bird ‘Flu caused by Avian Influenza occurs naturally in aquatic birds such as wild ducks, geese, swans, gulls but can also infect domestic poultry and other animal species too. It has also been known to infect humans, on occasion (e.g. H5N1, which continues to infect humans sporadically and is a cause of concern as it has  potential to become a pandemic virus).

Is Bird Flu different to human flu?

Avian Influenza is typically caused by Type A Influenza viruses (there are 4 types, A, B, C and D) which are separated into subtypes based on the proteins on their surface. You may have heard the viruses referred to as H5N1 or H1N1. These names denote for the differences in the proteins on their surface, which enable entry of the virus into cells. The H stands for Haemaglutinin (H) and the N stands for Neuraminidase. There are in total 18 H types and 11 N types, with a large number of combinations, some more pathogenic than others. 

Some subtypes are only found in certain animals and in certain locations around the world, hence the term “bird flu” or “swine flu” as asubtype typically found in birds or pigs (but are sometimes zoonotic, which means they can infect across to humans). There are only two main subtypes of Influenza A that are found in humans; H1N1 and H3N2 but humans have been known to be infected with other zoonotic types.

How deadly is Bird Flu to birds?

Avian influenza strains are categorized as Highly Pathogenic (HPAI) and Low Pathogenic (LPAI), based  on their ability to cause mortality infection in birds . In the UK each type of influenza is categorized into high or low pathogenicity and then monitored based upon this. HPAI infections can kill birds within 48 hours in 90-100% infections so these outbreaks must be swiftly controlled.  

Recent outbreaks of Bird Flu In the UK

Avian Influenza or Bird Flu is a notifiable disease in the UK, and if suspected in any type of bird must be reported immediately to DEFRA.

Due to recent outbreaks of Bird Flu in the UK, DEFRA have imposed an Avian Influenza Prevention Zone across the whole of the UK. This means that all poultry keepers must take the extra biosecurity measures set in place to protect their poultry from risk of bird flu from wild birds. Furthermore, all bird gatherings are prohibited. 

3 cases of Bird Flu have been confirmed in the UK recently:

Strain H5N8 detected in broilers in Leominster, Herefordshire on 11th November 2020 with HPAI. A 3km and 10km Temporary Control Zone have been put in place around the infected premises.

Strain HPAI H5N8 confirmed in Frodsham, Cheshire on the 2nd November 2020. A 3km Protection Zone and a 10km Surveillance Zone have also been put in place around the infected premises. 

LPAI H5N2 strain confirmed in Deal, Kent on 2nd November 2020. A 1km LPAI Restricted Zone has been put around the premises. 

You can check if your area is affected by these zones using this interactive map

Due to recent confirmed cases of Bird Flu, the risk level in wild birds has been raised from medium to high, on the 6thNovember 2020. 

Details of increased Biosecurity measures, how to report suspected bird flu and more information on the current status of outbreaks within the UK can be found here.

An updated outbreak assessment HPAI in UK and Europe was published on 6 November 2020 and can be found here.

References:

https://www.gov.uk/government/news/avian-influenza-bird-flu-national-prevention-zone-declared

https://www.gov.uk/guidance/avian-influenza-bird-flu#how-to-spot-avian-influenza

https://www.cdc.gov/flu/avianflu/index.htm